U.S. patent application number 15/774742 was filed with the patent office on 2018-11-15 for wireless communication system, a wireless device, network nodes, and methods therein, for changing master node for the wireless device.
The applicant listed for this patent is Telefonaktiebolaget LM Ericsson (publ). Invention is credited to Rui FAN, Qingyu MIAO, Stefan WAGER, Osman Nuri Can YILMAZ.
Application Number | 20180332657 15/774742 |
Document ID | / |
Family ID | 58719116 |
Filed Date | 2018-11-15 |
United States Patent
Application |
20180332657 |
Kind Code |
A1 |
FAN; Rui ; et al. |
November 15, 2018 |
Wireless Communication System, A Wireless Device, Network Nodes,
And Methods Therein, For Changing Master Node For The Wireless
Device
Abstract
A method performed in a wireless communications system for
changing master node for a wireless device (WD). A first node is
the master node for the WD, and second and third nodes are
secondary nodes for the WD. The third node receives information
that the third node is to be the master node and information to
reuse a first set of existing protocol entities and context for
communication with the WD. The WD receives information about a
change of master node from the first node to the third node and
information to reuse a second set of existing protocol entities and
context for communication with the third node. The second node
receives information that the third node is the master node and
information to reuse a third set of existing protocol entities and
context for communication with the WD. Thereby the master node for
the WD is changed.
Inventors: |
FAN; Rui; (BEIJING, CN)
; MIAO; Qingyu; (BEIJING, CN) ; WAGER; Stefan;
(ESPOO, FI) ; YILMAZ; Osman Nuri Can; (ESPOO,
FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Telefonaktiebolaget LM Ericsson (publ) |
Stockholm |
|
SE |
|
|
Family ID: |
58719116 |
Appl. No.: |
15/774742 |
Filed: |
November 18, 2015 |
PCT Filed: |
November 18, 2015 |
PCT NO: |
PCT/SE2015/051239 |
371 Date: |
May 9, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 36/38 20130101;
H04W 76/15 20180201; H04W 36/18 20130101; H04W 36/08 20130101; H04W
76/22 20180201; H04L 1/16 20130101; H04W 36/0069 20180801; H04W
76/20 20180201; H04W 84/20 20130101; H04W 36/0033 20130101; H04W
36/305 20180801 |
International
Class: |
H04W 84/20 20060101
H04W084/20 |
Claims
1.-32. (canceled)
33. A wireless communications system configured to change master
node for a wireless device, the wireless communication system
comprising: first, second, and third network nodes, wherein the
wireless device, the first network node, the second network node
and the third network node are operating in the wireless
communications system, wherein the first network node is the master
node for the wireless device, wherein the second network node and
the third network node are secondary nodes for the wireless device,
and wherein the wireless communications system is configured to:
receive a first signal using the third network node, which first
signal comprises information that the third network node is to be
the master node for the wireless device and information to the
third network node to reuse a first set of existing protocol
entities and context for communication with the wireless device;
receive transmit a second signal to the wireless device, which
second signal comprises information about a change of master node
from the first network node to the third network node and
information to the wireless device to reuse a second set of
existing protocol entities and context for communication with the
third network node; and receive a third signal using the second
network node, which third signal comprises information that the
third network node is the master node for the wireless device and
information to the second network node to reuse a third set of
existing protocol entities and context for communication with the
wireless device, whereby the master node for the wireless device is
changed.
34.-41. (canceled)
42. A wireless device configured to change master node for the
wireless device, wherein the wireless device, a first network node,
a second network node and a third network node are operating in a
wireless communications system, wherein the first network node is
the master node for the wireless device, wherein the second network
node and the third network node are secondary nodes for the
wireless device, and wherein the wireless device comprises: an
input/output interface configured to communicate with the wireless
communication system; and a processor configured to, receive a
second signal through the input/output interface, which second
signal comprises information about a change of master node from the
first network node to the third network node and information to the
wireless device to reuse a second set of existing protocol entities
and context for communication with the third network node.
43. The wireless device of claim 42, wherein the processor is
further configured to: transmit a first signal through the
input/output interface to the third network node, which first
signal comprises information that the third network node is to be
the master node for the wireless device and information to the
third network node to reuse a first set of existing protocol
entities and context for communication with the wireless
device.
44. The wireless device of claim 42, wherein the processor is
further configured to: receive the second signal from the first
network node or the third network node through the input/output
interface.
45. The wireless device of claim 42, wherein the processor is
further configured to: receive a first acknowledgement signal from
the third network node through the input/output interface, which
first acknowledgement signal acknowledges receipt of the first
signal.
46. The wireless device of claim 42, wherein the processor is
further configured to: transmit a second acknowledgement signal to
the third network node, which second acknowledgement signal
acknowledges receipt of the second signal.
47. The wireless device of claim 42, wherein the existing protocol
entities comprise one or more Radio Link Control, RLC, entities
and/or one or more Medium Access Control, MAC, entities, and
wherein the context comprises one or more of: state information
such as a Radio Resource Control, RRC, state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability.
48. The wireless device of claim 42, wherein the processor is
further configured to: derive a security key to be used in a radio
bearer between the wireless device and the third network node; and
configure a Packet Data Convergence Protocol, PDCP, entity for the
radio bearer between the wireless device and the third network
node.
49. A first network node configured to change master node for a
wireless device, wherein the wireless device, the first network
node, and a third network node are operating in a wireless
communications system, wherein the first network node is the master
node for the wireless device, wherein the third network node is a
secondary node for the wireless device, and wherein the first
network node comprises: an input/output interface configured to
communicate with the wireless device and with the second and third
network nodes; and a processor configured to, transmit a first
signal through the input/output interface to the third network
node, which first signal comprises information that the third
network node is to be the master node for the wireless device and
information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device; and transmit a second signal through the
input/output interface to the wireless device, which second signal
comprises information about a change of master node from the first
network node to the third network node and information to the
wireless device to reuse a second set of existing protocol entities
and context for communication with the third network node, whereby
the master node for the wireless device is changed.
50. The first network node of claim 49, wherein the processor is
further configured to: receive a first acknowledgement signal from
the third network node through the input/output interface, which
first acknowledgement signal acknowledges receipt of the first
signal.
51. The first network node of claim 49, wherein the existing
protocol entities comprise one or more Radio Link Control, RLC,
entities and/or one or more Medium Access Control, MAC, entities,
and wherein the context comprises one or more of: state information
such as a Radio Resource Control, RRC, state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability.
52. The first network node of claim 49, wherein the processor is
further configured to: prepare to receive data from the third
network node.
53.-57. (canceled)
58. A third network node configured to change master node for a
wireless device, wherein the wireless device, a first network node,
a second network node and the third network node are operating in a
wireless communications system, wherein the first network node is
the master node for the wireless device, wherein the second network
node and the third network node are secondary nodes for the
wireless device; and wherein the third network node comprises: an
input/output interface configured to communicate with the wireless
device and with the first and second network nodes; and a processor
configured to, receive a first signal through the input/output
interface, which first signal comprises information that the third
network node is to be the master node for the wireless device and
information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device; transmit a second signal through the network
interface to the wireless device, which second signal comprises
information about a change of master node from the first network
node to the third network node and information to the wireless
device to reuse a second set of existing protocol entities and
context for communication with the third network node; and transmit
a third signal through the network interface to the second network
node, which third signal comprises information that the third
network node is the master node for the wireless device and
information to the second network node to reuse a third set of
existing protocol entities and context for communication with the
wireless device, whereby the master node for the wireless device is
changed.
59. The third network node of claim 58, wherein the processor is
further configured to: receive the first signal from the first
network node or the wireless device through the input/output
interface.
60. The third network node of claim 58, wherein the processor is
further configured to: transmit a first acknowledgement signal
through the input/output interface to the first network node or the
wireless device, which first acknowledgement signal acknowledges
receipt of the first signal.
61. The third network node of claim 58, wherein the processor is
further configured to: receive a second acknowledgement signal from
the wireless device through the input/output interface, which
second acknowledgement signal acknowledges receipt of the second
signal.
62. The third network node of claim 58, wherein the processor is
further configured to: receive a third acknowledgement signal from
the second network node through the input/output interface, which
third acknowledgement signal acknowledges receipt of the third
signal.
63. The third network node of claim 58, wherein the existing
protocol entities comprise one or more Radio Link Control, RLC,
entities and/or one or more Medium Access Control, MAC, entities,
and wherein the context comprises one or more of: state information
such as a Radio Resource Controller, RRC, state; security-related
information such as a security capability or a security key; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability.
64. The third network node of claim 58, wherein the processor is
further configured to: transmit a fourth signal through the
input/output interface to a core network node, which fourth signal
informs the core network node that the third network node is the
master node for the wireless device.
65.-66. (canceled)
67. A method performed by a wireless device to change master node
for the wireless device, wherein the wireless device, a first
network node, a second network node and a third network node are
operating in a wireless communications system, wherein the first
network node is the master node for the wireless device, wherein
the second network node and the third network node are secondary
nodes for the wireless device, and wherein the method comprises:
receiving a second signal, which second signal comprises
information about a change of master node from the first network
node to the third network node and information to the wireless
device to reuse a second set of existing protocol entities and
context for communication with the third network node.
68. A method performed by a first network node to change master
node for a wireless device, wherein the wireless device, the first
network node, and a third network node are operating in a wireless
communications system, wherein the first network node is the master
node for the wireless device, wherein the third network node is a
secondary node for the wireless device, and wherein the method
comprises: transmitting a first signal to the third network node,
which first signal comprises information that the third network
node is to be the master node for the wireless device and
information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device; and transmitting a second signal to the wireless
device, which second signal comprises information about a change of
master node from the first network node to the third network node
and information to the wireless device to reuse a second set of
existing protocol entities and context for communication with the
third network node, whereby the master node for the wireless device
is changed.
69. A method performed by a third network node to change master
node for a wireless device, wherein the wireless device, a first
network node, a second network node and the third network node are
operating in a wireless communications system, wherein the first
network node is the master node for the wireless device, wherein
the second network node and the third network node are secondary
nodes for the wireless device; and wherein the method comprises:
receiving a first signal, which first signal comprises information
that the third network node is to be the master node for the
wireless device and information to the third network node to reuse
a first set of existing protocol entities and context for
communication with the wireless device; transmitting a second
signal to the wireless device, which second signal comprises
information about a change of master node from the first network
node to the third network node and information to the wireless
device to reuse a second set of existing protocol entities and
context for communication with the third network node; and
transmitting a third signal to the second network node, which third
signal comprises information that the third network node is the
master node for the wireless device and information to the second
network node to reuse a third set of existing protocol entities and
context for communication with the wireless device, whereby the
master node for the wireless device is changed.
Description
TECHNICAL FIELD
[0001] Embodiments herein relate to a wireless communications
system, a wireless device, a first network node, a second network
node, a third network node and to methods therein. Especially,
embodiments herein relates to changing master node for the wireless
device.
BACKGROUND
[0002] In the field of wireless communication, communication
devices such as terminals or wireless devices are also known as
e.g. User Equipments (UE), mobile terminals, wireless terminals
and/or mobile stations. Such terminals are enabled to communicate
wirelessly in a wireless communication system, such as a Wireless
Local Area Network (WLAN), or a cellular communications network,
sometimes also referred to as a cellular radio system or cellular
networks. The communication may be performed e.g. between two
terminals, between a terminal and a regular telephone, between a
terminal and an Access Point/Access Node (AP/AN), and/or between a
terminal and a server via an access network and possibly one or
more core networks, comprised within the communications
network.
[0003] The above terminals or wireless devices may further be
referred to as mobile telephones, cellular telephones, laptops, or
tablets with wireless capability, just to mention some further
examples. The terminals or wireless devices in the present context
may be, for example, portable, pocket-storable, hand-held,
computer-comprised, or vehicle-mounted mobile devices, enabled to
communicate voice and/or data, via the access network, such as a
Radio Access Network (RAN), with another entity, such as another
terminal or a server.
[0004] The communications network covers a geographical area which
is divided into geographical subareas, such as coverage areas,
cells or clusters. In a cellular communications network each cell
area is served by an access node such as a base station, e.g. a
Radio Base Station (RBS), which sometimes may be referred to as
e.g. "eNB", "eNodeB", "NodeB", "B node", or BTS (Base Transceiver
Station), depending on the technology and terminology used. The
base stations may be of different classes such as e.g. macro
eNodeB, home eNodeB or pico base station, based on transmission
power and thereby also cell size. A cell is the geographical area
where radio coverage is provided by the base station at a base
station site. One base station, situated at the base station site,
may serve one or several cells. Further, each base station may
support one or several communication technologies. The base
stations communicate over the air interface operating on radio
frequencies with the terminals or wireless devices within range of
the base stations. In the context of this disclosure, the
expression Downlink (DL) is used to denote the transmission path
from the base station to the mobile station. The expression Uplink
(UL) is used to denote the transmission path in the opposite
direction i.e. from the mobile station to the base station.
[0005] In 3rd Generation Partnership Project (3GPP) Long Term
Evolution (LTE), base stations, which may be referred to as eNodeBs
or even eNBs, may be directly connected to one or more core
networks.
[0006] 3GPP LTE radio access standard has been written in order to
support high bitrates and low latency both for uplink and downlink
traffic.
[0007] Dual Connectivity (DC) is a feature that has been
standardized in 3GPP for LTE. In Dual connectivity, a user
equipment (UE) can connect to two evolved Node Bs (eNBs)
concurrently. One of the two eNBs, called a Master eNB (MeNB), is
the signaling anchor point and the other one of the two eNBs,
called a Secondary eNB (SeNB), is used to further increase user
throughput. In DC, the frequency used by the MeNB and the SeNB,
respectively, is assumed to be different. This is schematically
illustrated in FIG. 1, wherein the UE is connected to the Master
eNB on a first carrier carrier1 and to the Secondary eNB on a
second carrier carrier2.
[0008] Further, in DC, there are three types of radio bearers; a
Master Cell Group (MCG) bearer, a Secondary Cell Group (SCG) bearer
and a Split bearer. The MCG bearer is a bearer served by the MeNB,
the SCG bearer is a bearer served by the SeNB, and the Split bearer
is a bearer served by both the MeNB and the SeNB. FIG. 2
schematically illustrates a combined protocol architecture
according to the prior art, wherein the radio bearers between the
PDCP, the RLC and the MAC layers to the left in the figure (dotted
lines) are served by the MeNB, the radio bearers between the PDCP,
the RLC and the MAC layers to the right in the figure (dashed
lines) are served by the SeNB and the radio bearers between the
PDCP, the RLC and the MAC layers in the middle are served by both
the MeNB and the SeNB.
[0009] Further, in DC, when the MeNB needs to be changed to another
eNB, whether it is the SeNB or another eNB, the signaling
procedure, i.e. the steps 301-316, illustrated in FIG. 3 has to be
followed. That is, the Serving SeNB (S-SeNB) needs to be released
first, cf. step 303, then the UE attaches to the Target eNB
(T-eNB), cf. steps 305-306, and thereafter the new SeNB, cf. steps
311-312, can be added.
[0010] The 5th generation mobile networks or 5th generation
wireless systems (5G) is the next major phase of mobile
telecommunications standards beyond the current 4G/IMT-Advanced
standards.
[0011] The Next Generation Mobile Networks Alliance defines several
requirements for the 5G communications networks. For example,
should data rates of several tens of megabits per second be
supported for tens of thousands of users. One (1) gigabit per
second should be offered simultaneously to tens of workers on the
same office floor. Several hundreds of thousands of simultaneous
connections should be supported for massive sensor deployments. The
spectral efficiency should be significantly enhanced as compared to
4G. The coverage should be improved, and the signalling efficiency
should be enhanced. Further, should the latency be reduced
significantly as compared to LTE. Furthermore, Critical Machine
Type Communication (C-MTC) is also an important use cases in 5G,
which has the ultra low latency requirement, and the latency
requirement is usually tightly connected to very ultra-reliability
requirements.
[0012] NeXt generation (NX) is envisioned to be a non-backward
compatible system in 5G. In NX, the frequency range targeted
includes 1 GHz up to 100 GHz. Especially due to the addition of
high frequency spectrum to the wireless operation, high gain
beamforming is a "must" to compensate the negative effects due to
unfavorable radio propagation properties. One issue with high gain
beamforming is that the serving beam is optimal only for a small
area, and expectedly a small fraction of time. When the UE moves,
the serving beam can deteriorate very fast which makes the mobility
in NX a challenge. In order to solve this issue, a cluster concept
is proposed for NX, where multiple access nodes can form a cluster
to serve UE together. When the UE moves, if the beam from one
access node deteriorates, other beams from other nodes can ensure
that the UE can still be served and receive good performance. FIG.
4 schematically illustrates a cluster in an NX communications
network. Especially, FIG. 4 schematically illustrates a UE-specific
serving cluster 400, wherein a group of ANs that are located in the
vicinity of a UE 402 are ready to serve the UE 402. In FIG. 4, the
exemplifying group of ANs comprises a Principal Serving Access Node
(P-SAN) 404 and two Assisting Serving Access Nodes (A-SANs) 406a,
406b. The P-SAN 404 is responsible for maintaining the connection
between the severing cluster 400 and the UE 402, and it is intended
to be the main serving AN for a given UE 402. Data blocks
associated with the UE 402 are communicated directly through the
P-SAN 404 most of the times. To control the fast beam switch, a
cluster head 410 is needed for the coordination in the cluster 400.
When the UE 402 moves, the standby AN 408a, 408b may also be added
to the cluster 400. The standby AN 408a, 408b may be added as P-SAN
or A-SAN.
[0013] However, it is a problem with current procedures for
switching master node for the UE, such as the procedure according
to FIG. 3 described above, that they are so time consuming whereby
requirements on low latency cannot be fulfilled. Further, the
signaling required for accomplishing the switching results in high
usage of radio resources which may cause interference and
deteriorate the performance in the communications network.
SUMMARY
[0014] An object of embodiments herein is to overcome the
above-mentioned drawbacks among others and to improve the
performance in a communications network.
[0015] According to a first aspect of embodiments herein, the
object is achieved by a method performed in a wireless
communications system for changing master node for a wireless
device. The wireless device, a first network node, a second network
node and a third network node are operating in the wireless
communications system. The first network node is the master node
for the wireless device, and the second network node and the third
network node are secondary nodes for the wireless device.
[0016] The third network node receives a first signal, which first
signal comprises information that the third network node is to be
the master node for the wireless device and information to the
third network node to reuse a first set of existing protocol
entities and context for communication with the wireless
device.
[0017] The wireless device receives a second signal, which second
signal comprises information about a change of master node from the
first network node to the third network node and information to the
wireless device to reuse a second set of existing protocol entities
and context for communication with the third network node.
[0018] The second network node receives a third signal which third
signal comprises information that the third network node is the
master node for the wireless device and information to the second
network node to reuse a third set of existing protocol entities and
context for communication with the wireless device.
[0019] Thereby the master node for the wireless device is
changed.
[0020] According to a second aspect of embodiments herein, the
object is achieved by a wireless communications system for changing
master node for a wireless device. The wireless device, a first
network node, a second network node and a third network node are
operating in the wireless communications system. The first network
node is the master node for the wireless device, and the second
network node and the third network node are secondary nodes for the
wireless device.
[0021] The third network node is configured to receive a first
signal, which first signal comprises information that the third
network node is to be the master node for the wireless device and
information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device.
[0022] The wireless device is configured to receive a second
signal, which second signal comprises information about a change of
master node from the first network node to the third network node
and information to the wireless device to reuse a second set of
existing protocol entities and context for communication with the
third network node.
[0023] The second network node is configured to receive a third
signal, which third signal comprises information that the third
network node is the master node for the wireless device and
information to the second network node to reuse a third set of
existing protocol entities and context for communication with the
wireless device, whereby the master node for the wireless device is
changed.
[0024] According to a third aspect of embodiments herein, the
object is achieved by a method performed by a method performed by a
wireless device for changing master node for the wireless device.
The wireless device, a first network node, a second network node
and a third network node are operating in the wireless
communications system. The first network node is the master node
for the wireless device, and the second network node and the third
network node are secondary nodes for the wireless device.
[0025] The wireless device receives a second signal, which second
signal comprises information about a change of master node from the
first network node to the third network node and information to the
wireless device to reuse a second set of existing protocol entities
and context for communication with the third network node.
[0026] According to a fourth aspect of embodiments herein, the
object is achieved by a wireless device for changing master node
for the wireless device. The wireless device, a first network node,
a second network node and a third network node are operating in the
wireless communications system. The first network node is the
master node for the wireless device, and the second network node
and the third network node are secondary nodes for the wireless
device.
[0027] The wireless device is configured to receive a second
signal, which second signal comprises information about a change of
master node from the first network node to the third network node
and information to the wireless device to reuse a second set of
existing protocol entities and context for communication with the
third network node.
[0028] According to a fifth aspect of embodiments herein, the
object is achieved by a method performed by a method performed by a
first network node for changing master node for a wireless device.
The wireless device, a first network node, a second network node
and a third network node are operating in the wireless
communications system. The first network node is the master node
for the wireless device, and the second network node and the third
network node are secondary nodes for the wireless device.
[0029] The first network node transmits a first signal to the third
network node, which first signal comprises information that the
third network node is to be the master node for the wireless device
and information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device.
[0030] Further, the first network node transmits a second signal to
the wireless device, which second signal comprises information
about a change of master node from the first network node to the
third network node and information to the wireless device to reuse
a second set of existing protocol entities and context for
communication with the third network node, whereby the master node
for the wireless device is changed.
[0031] According to a sixth aspect of embodiments herein, the
object is achieved by a first network node for changing master node
for a wireless device, wherein the wireless device. The wireless
device, a first network node, a second network node and a third
network node are operating in the wireless communications system.
The first network node is the master node for the wireless device,
and the second network node and the third network node are
secondary nodes for the wireless device.
[0032] The first network node is configured to transmit a first
signal to the third network node, which first signal comprises
information that the third network node is to be the master node
for the wireless device and information to the third network node
to reuse a first set of existing protocol entities and context for
communication with the wireless device.
[0033] Further, the first network node is transmit a second signal
to the wireless device, which second signal comprises information
about a change of master node from the first network node to the
third network node and information to the wireless device to reuse
a second set of existing protocol entities and context for
communication with the third network node, whereby the master node
for the wireless device is changed.
[0034] According to a seventh aspect of embodiments herein, the
object is achieved by a method performed by a second network node
for assisting in changing master node for a wireless device. The
wireless device, a first network node, a second network node and a
third network node are operating in the wireless communications
system. The first network node is the master node for the wireless
device, and the second network node and the third network node are
secondary nodes for the wireless device.
[0035] The second network node receives a third signal, which third
signal comprises information that the third network node is the
master node for the wireless device and information to the second
network node to reuse a third set of existing protocol entities and
context for communication with the wireless device, whereby the
second network node assists in changing master node for the
wireless device.
[0036] According to an eighth second aspect of embodiments herein,
the object is achieved by a second network node for assisting in
changing master node for a wireless device. The wireless device, a
first network node, a second network node and a third network node
are operating in the wireless communications system. The first
network node is the master node for the wireless device, and the
second network node and the third network node are secondary nodes
for the wireless device.
[0037] The second network node is configured to receive a third
signal, which third signal comprises information that the third
network node is the master node for the wireless device and
information to the second network node to reuse a third set of
existing protocol entities and context for communication with the
wireless device, whereby the second network node assists in
changing master node for the wireless device.
[0038] According to a ninth aspect of embodiments herein, the
object is achieved by a method performed a third network node for
changing master node for a wireless device. The wireless device, a
first network node, a second network node and a third network node
are operating in the wireless communications system. The first
network node is the master node for the wireless device, and the
second network node and the third network node are secondary nodes
for the wireless device.
[0039] The third network node receives a first signal, which first
signal comprises information that the third network node is to be
the master node for the wireless device and information to the
third network node to reuse a first set of existing protocol
entities and context for communication with the wireless
device.
[0040] Further, the third network node transmits a second signal to
the wireless device, which second signal comprises information
about a change of master node from the first network node to the
third network node and information to the wireless device to reuse
a second set of existing protocol entities and context for
communication with the third network node.
[0041] Furthermore, the third network node transmits a third signal
to the second network node, which third signal comprises
information that the third network node is the master node for the
wireless device and information to the second network node to reuse
a third set of existing protocol entities and context for
communication with the wireless device, whereby the master node for
the wireless device is changed.
[0042] According to a tenth aspect of embodiments herein, the
object is achieved by a third network node for changing master node
for a wireless device. The wireless device, a first network node, a
second network node and a third network node are operating in the
wireless communications system. The first network node is the
master node for the wireless device, and the second network node
and the third network node are secondary nodes for the wireless
device.
[0043] The third network node is configured to receive a first
signal, which first signal comprises information that the third
network node is to be the master node for the wireless device and
information to the third network node to reuse a first set of
existing protocol entities and context for communication with the
wireless device.
[0044] Further, the third network node is configured to transmit a
second signal to the wireless device, which second signal comprises
information about a change of master node from the first network
node to the third network node and information to the wireless
device to reuse a second set of existing protocol entities and
context for communication with the third network node.
[0045] Furthermore, the third network node is configured to
transmit a third signal to the second network node, which third
signal comprises information that the third network node is the
master node for the wireless device and information to the second
network node to reuse a third set of existing protocol entities and
context for communication with the wireless device, whereby the
master node for the wireless device is changed.
[0046] According to an eleventh aspect of embodiments herein, the
object is achieved by a computer program, comprising instructions
which, when executed on at least one processor, causes the at least
one processor to carry out the method performed by the wireless
device.
[0047] According to a twelfth aspect of embodiments herein, the
object is achieved by a computer program, comprising instructions
which, when executed on at least one processor, causes the at least
one processor to carry out the method performed by the first
network node.
[0048] According to a thirteenth aspect of embodiments herein, the
object is achieved by a computer program, comprising instructions
which, when executed on at least one processor, causes the at least
one processor to carry out the method performed by the 25 second
network node.
[0049] According to a fourteenth aspect of embodiments herein, the
object is achieved by a computer program, comprising instructions
which, when executed on at least one processor, causes the at least
one processor to carry out the method performed by the third
network node.
[0050] According to a fifteenth aspect of embodiments herein, the
object is achieved by a carrier comprising the computer program,
wherein the carrier is one of an electronic signal, an optical
signal, a radio signal or a computer readable storage medium.
[0051] Since the third network node receives a first signal, which
first signal comprises information that the third network node is
to be the master node for the wireless device and information to
the third network node to reuse a first set of existing protocol
entities and context for communication with the wireless device;
since the wireless device receives a second signal, which second
signal comprises information about a change of master node from the
first network node to the third network node and information to the
wireless device to reuse a second set of existing protocol entities
and context for communication with the third network node; and
since the second network node receives a third signal which third
signal comprises information that the third network node is the
master node for the wireless device and information to the second
network node to reuse a third set of existing protocol entities and
context for communication with the wireless device, already
existing protocol entities and context for communication can be
reused. Thereby, a fast role-switch from one master node to another
is accomplished. This results in an improved performance in the
communications network.
[0052] An advantage with embodiments herein is that a reduced
signaling for role-switch is provided, which reduces the handover
interruption time and avoids the radio link failure, resulting in
an improved availability of the communications network and in a
seamless mobility for the wireless device with low latency and high
reliability. Thereby the requirements on a 5G communications
network, especially the requirement for C-MTC is fulfilled.
[0053] By the expression "seamless mobility" when used in this
disclosure is meant that the handover interruption time is short,
e.g. that the handover interruption time is zero.
BRIEF DESCRIPTION OF DRAWINGS
[0054] Examples of embodiments herein will be described in more
detail with reference to attached drawings in which:
[0055] FIG. 1 schematically illustrates dual connectivity in
LTE;
[0056] FIG. 2 schematically illustrates a combined protocol
architecture according to prior art;
[0057] FIG. 3 schematically illustrates the signaling procedure for
change of master node according to prior art;
[0058] FIG. 4 schematically illustrates an exemplifying cluster in
an NX communications network;
[0059] FIG. 5 schematically illustrates an embodiment of a
communications network;
[0060] FIG. 6 is a combined flowchart and block diagram
illustrating embodiments of a method performed in the
communications network;
[0061] FIG. 7 is a flowchart depicting embodiments of a method
performed by a wireless device;
[0062] FIG. 8 is a schematic block diagram illustrating embodiments
of a wireless device;
[0063] FIG. 9 is a flowchart depicting embodiments of a method
performed by a first network node;
[0064] FIG. 10 is a schematic block diagram illustrating
embodiments of a first network node;
[0065] FIG. 11 is a flowchart depicting embodiments of a method
performed by a second network node;
[0066] FIG. 12 is a schematic block diagram illustrating
embodiments of a second network node;
[0067] FIG. 13 is a flowchart depicting embodiments of a method
performed by a third network node;
[0068] FIG. 14 is a schematic block diagram illustrating
embodiments of a third network node;
[0069] FIG. 15 schematically illustrates embodiments of a first
protocol architecture;
[0070] FIG. 16 schematically illustrates embodiments of a second
protocol architecture;
[0071] FIG. 17 schematically illustrates embodiments of the
signaling procedure for change of master node for a wireless
device; and
[0072] FIG. 18 schematically illustrates embodiments of the
signaling procedure for change of master node a wireless
device.
DETAILED DESCRIPTION
[0073] Some embodiments disclosed herein relate to the fifth
generation (5G) of wireless communications networks, and especially
to changing master node for a wireless device operating in the
wireless communications network.
[0074] An aim of some embodiments herein is to provide for handling
of connections in conjunction with multiple access nodes to enable
a seamless and always-available operation. By the expression
"seamless and always-available operation" when used in this
disclosure is meant an operation with a short or no handover
interruption time.
[0075] As part of developing embodiments herein, some problems with
the state of the art communications networks will first be
identified and discussed.
[0076] Currently it is not decided how to handle a role switch
between network nodes operating in a future communications network,
such as a 5G-NX communications network. For example, it is not
decided how to handle a change of master node for a wireless device
operating in the communications network. The change of master node
from one node to another is sometimes in this disclosure referred
to as a role-switch since there is a switch in roles between a
first node acting as master node for the wireless device and a
second node acting as a secondary node for the wireless device.
[0077] The seamless and always-available operation may be
accomplished either for a) enabling a fast role-switch, i.e., when
a secondary network node, e.g. a SeNB, is better than a master
network node, e.g. a MeNB, and therefore should be the new master
network node, or for b) guaranteeing a communications network
availability, i.e., when the master network node, e.g. the MeNB,
suddenly is out-of-service and the secondary network node, e.g. the
SeNB, needs to be upgraded to be the master network node.
[0078] One straightforward solution is to follow the same principle
as defined in LTE DC described above. During such as LTE DC
procedure, the old members in the old cluster needs to be first
released, after that the UE connects to the new MeNB and a new
cluster can be set up with the new members included. By the
expression "old members in the old cluster" is meant the master
network node and the one or more secondary network nodes serving
the wireless device before the role-switch. Further, by the
expression "new members in the new cluster" is meant the master
network node and the one or more secondary network nodes serving
the wireless device after the role-switch. However, the LTE DC
procedure described above is neither a signaling-efficient
procedure nor a time-optimized procedure as too many signaling is
involved in the role switch. Furthermore, if there is a
disconnection, e.g. a connection failure, between the master node,
e.g. the MeNB, and the wireless device, there may be even a longer
delay to perform recovery from the secondary node, e.g. the SeNB,
which is not acceptable for certain type of applications and/or
services e.g., for a mission-critical Machine Type Communication
(MTC). All in all, such as LTE DC procedure does not satisfy the
requirement for 5G applications which may require fast role switch
for Critical Machine Type Communication (C-MTC).
[0079] Therefore, some embodiments disclosed herein provide for a
more efficient signaling procedure for handling of role-switch in a
communications network. The role-switch may occur either when the
master node, e.g. the MeNB, actively requires a secondary node,
e.g. the SeNB, to take the role as master node; or when the master
node, e.g. the MeNB, is associated with a failure and the secondary
node, e.g. the SeNB, has to be upgraded to take the role as master
node.
[0080] With the new signaling procedure, many entities, e.g.
protocol entities, and context in the cluster are kept. Thereby,
the signaling needed for accomplishing the role-switch is reduced.
Thus, unnecessary signaling is avoided or reduced, whereby the
role-switch procedure is accelerated which is beneficial in 5G
scenarios where fast response and availability are needed.
[0081] Some embodiments disclosed herein provide for a new protocol
architecture and a new signaling procedure that is designed to
solve the role-switch or recovery issue in a connectivity cluster.
By the expression "connectivity cluster" when used in this
disclosure is meant a group of access nodes and/or connections that
are located in the vicinity of a wireless device, e.g. a UE, and
are ready to serve the wireless device. By embodiments described
herein, the amount of signaling required is reduced and the
role-switching procedure is expedited which is essential for a
delay sensitive application and/or a delay sensitive service, such
as mission-critical MTC.
Terminology
[0082] The following terminology is used in embodiments described
herein and is elaborated below:
[0083] Network node: In some embodiments a more general term
"network node" is used and it may correspond to any type of network
node or radio network node, which communicates with a UE and/or
with another network node. Examples of network nodes are User
equipment (UE), NodeB, MeNB, SeNB, a network node belonging to a
Master Cell Group (MCG) or a Secondary Cell Group (SCG), Base
Station (BS), multi-Standard Radio (MSR) radio node such as MSR BS,
eNodeB, network controller, radio Network Controller (RNC), Base
Station Controller (BSC), relay, donor node controlling relay, Base
Transceiver Station (BTS), Access Point (AP), transmission points,
transmission nodes, Radio Remote Unit (RRU), Remote Radio Head
(RRH), nodes in Distributed Antenna System (DAS), core network node
(e.g. Mobile Switching Center (MSC), Mobility Management Entity
(MME) etc), Operations and Maintenance (O&M), Operations
Support System (OSS), Self-organizing Network (SON), positioning
node (e.g. Enhanced Serving Mobile Location Center (E-SMLC)),
Mobile Data Terminal (MDT) etc.
[0084] Communication device/User equipment/wireless device: In some
embodiments the non-limiting terms communications device, wireless
device and User Equipment (UE) are used and they refer to any type
of wireless device communicating with a network node or with
another UE in a wireless, cellular or mobile communication system.
Examples of communication device/UE/wireless device are
Device-to-Device (D2D) UE, machine type UE or UE capable of machine
to machine (M2M) communication, Personal Digital Assistant (PDA),
Tablet, wireless terminal, mobile terminals, mobile phone, smart
phone, Laptop Embedded Equipped (LEE), Laptop Mounted Equipment
(LME), Universal Serial Bus (USB) dongles etc.
[0085] It should be noted that the term user equipment used in this
document also covers other wireless devices such as Machine to
Machine (M2M) devices, even though they are not handled by any
user.
[0086] Further, in this disclosure the terms communications device,
wireless device and UE are used interchangeably.
[0087] General
[0088] Note that although terminology from 3GPP LTE has been used
in this disclosure to exemplify embodiments, this should not be
seen as limiting the scope of the invention to only the
aforementioned system. Other wireless systems, including Wideband
Code Division Multiple Access (WCDMA), High Speed Packet Access
(HSPA), Worldwide Interoperability for Microwave Access (WiMax),
WiFi, Wireless Local Area Network (WLAN), IEEE802.11 system and
Global System for Mobile Communications (GSM)/GSM EDGE Radio Access
Network (GERAN), may also benefit from exploiting the ideas covered
within this disclosure.
[0089] Also note that terminology such as eNodeB and UE should be
considering non-limiting and does in particular not imply a certain
hierarchical relation between the two; in general "eNodeB" could be
considered as device 1 and "UE" device 2, and these two devices
communicate with each other over some radio channel.
[0090] Further, the description frequently refers to wireless
transmissions in the downlink, but embodiments herein are equally
applicable in the uplink.
[0091] Furthermore, by the expression "protocol layer entity" when
used herein is meant a Packet Data Convergence Protocol (PDCP)
entity, a Radio Link Control (RLC) entity, Media Access Control
(MAC) entity, or another protocol layer entity.
[0092] In the following section, embodiments herein will be
illustrated in more detail by various exemplary embodiments. It
should be noted that these embodiments are not mutually exclusive.
Components from one embodiment may be assumed to be present in
another embodiment and it will be obvious to a person skilled in
the art how those components may be used in the other exemplary
embodiments.
[0093] FIG. 5 depicts an example of a communications network 500 in
which embodiments herein may be implemented. The communications
network 500 is a wireless communication network such as an NX
network, an LTE network, a WCDMA network, a GSM network, any 3GPP
cellular network, WiMAX network, any other wireless network, or a
combination of one or more of the aforementioned communications
networks.
[0094] A Radio Access Network (RAN) 501 may be comprised in the
communications network 500. The RAN 501 may be an NX access
network, an LTE access network, a WCDMA access network, a GSM
access network, any 3GPP cellular access network, WiMAX access
network, any other wireless access network, or a combination of one
or more of the aforementioned access networks.
[0095] A core network 502 may be comprised in the communications
network 500. The core network 502 may be an NX core network, an LTE
Core network, e.g. a System Architecture Evolution (SAE) network, a
WCDMA core network, an GSM core network, any 3GPP cellular core
network, a Wimax core network, any other wireless core network, or
a combination of one or more of the aforementioned core
networks.
[0096] A core network node 504 may be comprised in or connected to
the core network 503. The core network node 504 may be an NX core
network node, an LTE core network node, a WCDMA core network node,
an GSM core network node, any 3GPP cellular core network node, a
Wimax core network node, or any other core network node.
[0097] A communications device, such as a wireless device 506 may
be comprised in the communications network 500 The wireless device
506 is configured to operate in the communications network 500. In
other words, the wireless device 506 is operable in the
communications network 500.
[0098] Further, in this disclosure, the terms communications
device, wireless device, UE and similar are used
interchangeably.
[0099] A first network node 508 may be comprised in the
communications network 500. The first network node 508 is
configured to operate in the communications network 500. In other
words, the first network node 508 is operable in the communications
network 500.
[0100] A first geographical area 508a is served by the first
network node 508. Further, the wireless device 506 is configured to
communicate with the first network node 508 when located in the
first geographical area 508a. The geographical area may be a wide
area or a beam.
[0101] A second network node 510 may be comprised in the
communications network 500. The second network node 510 is
configured to operate in the communications network 500. In other
words, the second network node 510 is operable in the
communications network 500.
[0102] A second geographical area 510a is served by the second
network node 510. Further, the wireless device 506 is configured to
communicate with the second network node 510 when located in the
first geographical area 510a.
[0103] A third network node 512 may be comprised in the
communications network 500. The third network node 512 is
configured to operate in the communications network 500. In other
words, the third network node 512 is operable in the communications
network 500.
[0104] A third geographical area 512a is served by the third
network node 512. Further, the wireless device 506 is configured to
communicate with the third network node 512 when located in the
third geographical area 512a.
[0105] Sometimes herein the first, second and third geographical
areas 508a, 510a, 512a are referred to as a cluster 514. In such
case, one or more of the first, second and third network nodes 508,
510, 512 located in the vicinity of the wireless device 506 and
ready to serve the wireless device 506 are said to be comprised in
or belonging to the cluster 514.
[0106] An example of a method performed in the communications
network 500 for changing master node for the wireless device 506
will now be described with reference to the combined flowchart and
block diagram illustrated in FIG. 6. As mentioned above, the
wireless device 506, the first network node 508, the second network
node 510 and the third network node 512 are operating in the
wireless communications system 500. Further, the first network node
508 is the master node for the wireless device 506, and the second
network node 510 and the third network node 512 are secondary nodes
for the wireless device 506.
[0107] Action 601
[0108] In order to inform the third network node 512 that it is to
be the new master node for the wireless device 506, the third
network node 512 receives a first signal S61. As illustrated in
FIG. 6, the first signal S61 may be transmitted from the wireless
device 506 or the first network node 508. The first signal S61 may
be transmitted from the wireless device 506 when the wireless
device 506 has detected a connection failure with the existing
master node, e.g., with the first network node 508. Alternatively,
the signal S61 may be transmitted from the first network node 508
acting as the master node, when the first network node 508 has
detected that the third network node 512 would be a better master
node than the first network node 508. By the expression "better
master node" is meant a network node providing an improved
communication quality for the wireless device 506.
[0109] The first signal S61 comprises information that the third
network node 512 is to be the master node for the wireless device
506 and information to the third network node 512 to reuse a first
set of existing protocol entities and context for communication
with the wireless device 506. Thus, the first signal S61
instructions the third network node 512 to be the master node and
to reuse already existing protocol entities and context for
communication with the wireless device 506.
[0110] The existing protocol entities comprise one or more Radio
Link Control (RLC) entities and/or one or more Medium Access
Control (MAC) entities, and wherein the context comprises one or
more of: state information such as a Radio Resource Control (RRC)
state; security-related information such as a security capability
or a security key; a UE identity such as an identity of a
UE-associated logical S1-connection; and a UE radio access
capability.
[0111] Thus, the first set of existing protocol entities and
context for communication with the wireless device 506 may comprise
one or more of the protocol entities and context mentioned above
and already existing and/or established for communicating with the
wireless device 506. For example, the first set of existing
protocol entities and context for communication with the wireless
device 506 may comprise the RLC entity and the security key,
etc.
[0112] Action 602
[0113] In order to inform the wireless device 506 about a change of
master node, the wireless device 506 receives a second signal S62.
As illustrated in FIG. 6, the second signal S62 may be transmitted
from the first network node 508 or from the third network node
512.
[0114] The second signal S62 comprises information about a change
of master node from the first network node 508 to the third network
node 512 and information to the wireless device 506 to reuse a
second set of existing protocol entities and context for
communication with the third network node 512. Thus, the second
signal S62 informs the wireless device 506 about the change of
master node and instructs the wireless device 506 to reuse already
existing protocol entities and context for communication with the
new master node, e.g. with the third network node 512.
[0115] The second set of existing protocol entities and context for
communication with the third network node 512 may comprise one or
more of the protocol entities and context mentioned above under
Action 601 and already existing and/or established for
communicating with the third network node 512. For example, the
second set of existing protocol entities and context for
communication with the third network node 512 may comprise the RLC
entity and the security key, etc.
[0116] Action 603
[0117] In order to inform the second network node 510 about a
change of master node, the second network node 510 receives a third
signal S63. As illustrated in FIG. 6, the third signal S63 is
transmitted by the third network node 512.
[0118] The third signal S63 comprises information that the third
network node 512 is the master node for the wireless device 506 and
information to the second network node 510 to reuse a third set of
existing protocol entities and context for communication with the
wireless device 506. Thus, the third signal S63 informs the second
network node 510 about the change of master node and instructs the
second network node 510 to reuse already existing protocol entities
and context for communication with the wireless device 506.
[0119] The third set of existing protocol entities and context for
communication with the wireless device 506 may comprise one or more
of the protocol entities and context mentioned above under Action
601 and already existing and/or established for communicating with
the wireless device 506. For example, the third set of existing
protocol entities and context for communication with the wireless
device 506 may comprise the RLC entity and the security key,
etc.
[0120] Following the Actions 601-603 described above the master
node for the wireless device 506 is changed. However, some
embodiments disclosed herein also comprise one or more of Actions
604-607, which will be described below.
[0121] Action 604
[0122] In response to the received first signal S61, the third
network node 512 may transmit a first acknowledgement signal S64 to
the transmitter of the first signal S61, e.g. to the wireless
device 506 or the first network node 508. The first acknowledgement
signal S64 acknowledges receipt of the first signal S61 informing
the third network node 512 about the change of master node.
[0123] Action 605
[0124] In response to the received second signal S62, the wireless
device 506 may transmit a second acknowledgement signal S65 to the
transmitter of the second signal S62, e.g. to the first network
node 508 or the third network node 512. The second acknowledgement
signal S65 acknowledges receipt of the second signal S62.
[0125] Action 606
[0126] In response to the received third signal S63, the second
network node 510 may transmit a third acknowledgement signal S66 to
the transmitter of the third signal S63, e.g. to the third network
node 512. The third acknowledgement signal S66 acknowledges receipt
of the third signal S63.
[0127] Action 607
[0128] The third network node 512 may transmit a fourth signal S67
to a core network node 504. The fourth signal S67 informs the core
network node 504 that the third network node 512 is the master node
for the wireless device 506.
[0129] An example of a method performed by the wireless device 506
for changing master node for the wireless device 506 will now be
described with reference to a flowchart illustrated in FIG. 7. As
mentioned above, the wireless device 506, the first network node
508, the second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0130] The method comprises one or more of the following actions.
It should be understood that some actions are optional, that some
actions may be taken in another suitable order and that actions may
be combined.
[0131] Action 701
[0132] In some embodiments, the wireless device 506 transmits a
first signal S61 to the third network node 512. This is done to
inform the third network node 512 about the change of master node
for the wireless device 506. As previously mentioned, the first
signal S61 comprises information that the third network node 512 is
to be the master node for the wireless device 506 and information
to the third network node 512 to reuse a first set of existing
protocol entities and context for communication with the wireless
device 506.
[0133] As mentioned above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506.
[0134] This action corresponds to Action 601 described above.
[0135] Action 702
[0136] The wireless device 506 receives a second signal S62. This
is done to inform the third wireless device 506 about the change of
master node. As mentioned above, the second signal S62 comprises
information about a change of master node from the first network
node 508 to the third network node 512 and information to the
wireless device 506 to reuse a second set of existing protocol
entities and context for communication with the third network node
512.
[0137] As previously mentioned, the second set of existing protocol
entities and context for communication with the third network node
512 may comprise one or more of the protocol entities and context
mentioned above under Action 701 and already existing and/or
established for communicating with the third network node 512.
[0138] In some embodiments, the wireless device 506 receives the
second signal S62 from the first network node 508 or the third
network node 512.
[0139] This action corresponds to Action 602 described above.
[0140] Action 703
[0141] The wireless device 506 may receive a first acknowledgement
signal S64 from the third network node 512. The first
acknowledgement signal S64 acknowledges receipt of the first signal
S61 at the third network node 512.
[0142] This action corresponds to Action 604 described above.
[0143] Action 704
[0144] In order to acknowledge receipt of the second signal S62,
the wireless device 506 may transmit a second acknowledgement
signal S65 to the third network node 512.
[0145] This action corresponds to Action 605 described above.
[0146] Action 705
[0147] In some embodiments, the wireless device 506 derive a
security key to be used in a radio bearer between the wireless
device 506 and the third network node 512. The radio bearer may be
a data radio bearer, e.g. a user data radio bearer, or a signaling
radio bearer.
[0148] Action 706
[0149] The wireless device 506 may configure a Packet Data
Convergence Protocol (PDCP) entity for the radio bearer between the
wireless device 506 and the third network node 512. The PDCP entity
may be a PDCP entity for a data radio bearer or a signaling radio
bearer.
[0150] To perform the method for changing master node for the
wireless device 506, the wireless device 506 may be configured
according to an arrangement depicted in FIG. 8. As mentioned above,
the wireless device 506, the first network node 508, the second
network node 510 and the third network node 512 are operating in
the wireless communications system 500. Further, the first network
node 508 is the master node for the wireless device 506, and the
second network node 510 and the third network node 512 are
secondary nodes for the wireless device 506.
[0151] In some embodiments, the wireless device 506 comprises an
input and output interface 800 configured to communicate with one
or more the network nodes e.g. the first, second and third network
nodes 508,510,512. The input and output interface 800 may comprise
a wireless receiver (not shown) and a wireless transmitter (not
shown).
[0152] The wireless device 506 is configured to receive, by means
of a receiving module 801 configured to receive, a signal from a
network node, e.g. from the first, second or third network node
508,510,512. The receiving module 801 may be implemented by or
arranged in communication with a processor 806 of the wireless
device 506. The processor 806 will be described in more detail
below.
[0153] The wireless device 506 is configured to receive a second
signal S62, which second signal S62 comprises information about a
change of master node from the first network node 508 to the third
network node 512 and information to the wireless device 506 to
reuse a second set of existing protocol entities and context for
communication with the third network node 512.
[0154] As previously mentioned, the second set of existing protocol
entities and context for communication with the third network node
512 may comprise one or more of the protocol entities and context
mentioned above under Action 701 and already existing and/or
established for communicating with the third network node 512.
Thus, the second set of existing protocol entities and context may
comprise one or more of the existing protocol entities and context
for communication with the third network node 512.
[0155] The wireless device 506 may be configured to receive the
second signal S62 from the first network node 508 or the third
network node 512.
[0156] In some embodiments, the wireless device 506 is configured
to receive a first acknowledgement signal S64 from the third
network node 512, which first acknowledgement signal S64
acknowledges receipt of the first signal S61.
[0157] The wireless device 506 is configured to transmit, by means
of a transmitting module 802 configured to transmit, a signal to a
network node, e.g. to the first, second or third network node
508,510,512. The transmitting module 802 may be implemented by or
arranged in communication with the processor 806 of the wireless
device 506.
[0158] The wireless device 506 may be configured to transmit a
first signal S61 to the third network node 512, which first signal
S61 comprises information that the third network node 512 is to be
the master node for the wireless device 506 and information to the
third network node 512 to reuse a first set of existing protocol
entities and context for communication with the wireless device
506.
[0159] As mentioned above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506.
[0160] In some embodiments, the wireless device 506 is configured
to transmit a second acknowledgement signal S65 to the third
network node 512, which second acknowledgement signal S65
acknowledges receipt of the second signal S62.
[0161] The wireless device 506 may be configured to derive, by
means of a deriving module 803 configured to derive, a security key
to be used in a radio bearer between the wireless device 506 and
the third network node 512. The deriving module 803 may be
implemented by or arranged in communication with the processor 806
of the wireless device 506.
[0162] As previously mentioned, the radio bearer may be data radio
bearer, e.g. a user data radio bearer, or a signalling radio
bearer.
[0163] The wireless device 506 may be configured to configure, e.g.
reconfigure, by means of a configuring module 804 configured to
configure, a Packet Data Convergence Protocol (PDCP) entity for the
radio bearer between the wireless device 506 and the third network
node 512. The configuring module 804 may be implemented by or
arranged in communication with the processor 806 of the wireless
device 506.
[0164] The wireless device 506 may also comprise means for storing
data. In some embodiments, the wireless device 506 comprises a
memory 805 configured to store the data. The data may be processed
or non-processed data and/or information relating thereto. The
memory 805 may comprise one or more memory units. Further, the
memory 805 may be a computer data storage or a semiconductor memory
such as a computer memory, a read-only memory, a volatile memory or
a non-volatile memory. The memory is arranged to be used to store
obtained information, data, configurations, schedulings, and
applications etc. to perform the methods herein when being executed
in the wireless device 506.
[0165] Embodiments herein for changing master node for the wireless
device 506 may be implemented through one or more processors, such
as the processor 806 in the arrangement depicted in FIG. 8,
together with computer program code for performing the functions
and/or method actions of embodiments herein. The program code
mentioned above may also be provided as a computer program product,
for instance in the form of a data carrier carrying computer
program code for performing the embodiments herein when being
loaded into the wireless device 506. One such carrier may be in the
form of an electronic signal, an optical signal, a radio signal or
a computer readable storage medium. The computer readable storage
medium may be a CD ROM disc or a memory stick.
[0166] The computer program code may furthermore be provided as
program code stored on a server and downloaded to the wireless
device 506.
[0167] Those skilled in the art will also appreciate that the
input/output interface 800, the receiving module 801, the
transmitting module 802, the deriving module 803 and the
configuring module 504 above may refer to a combination of analog
and digital circuits, and/or one or more processors configured with
software and/or firmware, e.g. stored in the memory 805, that when
executed by the one or more processors such as the processors in
the wireless device 506 perform as described above. One or more of
these processors, as well as the other digital hardware, may be
included in a single Application-Specific Integrated Circuitry
(ASIC), or several processors and various digital hardware may be
distributed among several separate components, whether individually
packaged or assembled into a System-on-a-Chip (SoC).
[0168] An example of a method performed by the first network node
508 for changing master node for the wireless device 506 will now
be described with reference to a flowchart illustrated in FIG. 9.
As mentioned above, the wireless device 506, the first network node
508, the second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0169] The method comprises one or more of the following actions.
It should be understood that some actions are optional, that some
actions may be taken in another suitable order and that actions may
be combined.
[0170] Action 901
[0171] The first network node 508 transmits a first signal S61 to
the third network node 512, which first signal S61 comprises
information that the third network node 512 is to be the master
node for the wireless device 506 and information to the third
network node 512 to reuse a first set of existing protocol entities
and context for communication with the wireless device 506.
[0172] This action corresponds to Action 601 described above.
[0173] Action 902
[0174] The first network node 508 transmits a second signal S62 to
the wireless device 506, which second signal S62 comprises
information about a change of master node from the first network
node 508 to the third network node 512 and information to the
wireless device 506 to reuse a second set of existing protocol
entities and context for communication with the third network node
512. Thereby the master node for the wireless device 506 is
changed.
[0175] As previously above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the second
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the third network node 512.
[0176] This action corresponds to Action 602 described above.
[0177] Action 903
[0178] In some embodiments, the first network node 508 receives a
first acknowledgement signal S64 from the third network node 512,
which first acknowledgement signal S64 acknowledges receipt of the
first signal S61.
[0179] This action corresponds to Action 604 described above.
[0180] Action 904
[0181] In some embodiments, the first network node 508 prepares to
receive data from the third network node 512. For example, the
first network node 508 may prepare to receive data from the third
network node 512 by setting up a tunnel using a GPRS Tunneling
Protocol (GTP), e.g. a GTP tunnel, between the first network node
508 and the third network node 512. A Tunnel Endpoint IDentifier
(TEID) of the GTP tunnel may be the third network node 512.
[0182] To perform the method for changing master node for the
wireless device 506, the first network node 508 may be configured
according to an arrangement depicted in FIG. 10. As mentioned
above, the wireless device 506, the first network node 508, the
second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0183] In some embodiments, the first network node 508 comprises an
input and output interface 1000 configured to communicate with one
or more wireless device, e.g. the wireless device 506, or one or
more the network nodes e.g. the second or third network nodes
510,512. The input and output interface 1000 may comprise a
wireless receiver (not shown) and a wireless transmitter (not
shown).
[0184] The first network node 508 is configured to receive, by
means of a receiving module 1001 configured to receive, a signal
from a wireless device, e.g. the wireless device 506 or a network
node, e.g. from the second or third network node 510,512. The
receiving module 1001 may be implemented by or arranged in
communication with a processor 1005 of the first network node 508.
The processor 1005 will be described in more detail below.
[0185] In some embodiments, the first network node 508 is
configured to receive a first acknowledgement signal S64 from the
third network node 512, which first acknowledgement signal S64
acknowledges receipt of a first signal S61 transmitted from the
first network node 508 to the third network node 512.
[0186] The first network node 508 is configured to transmit, by
means of a transmitting module 1002 configured to transmit, a
signal to a wireless device, e.g. the wireless device 506, or to a
network node, e.g. to the second or third network node 510,512. The
transmitting module 1002 may be implemented by or arranged in
communication with the processor 1005 of the first network node
508.
[0187] The first network node 508 is configured to transmit a first
signal S61 to the third network node 512. The first signal S61
comprises information that the third network node 512 is to be the
master node for the wireless device 506 and information to the
third network node 512 to reuse a first set of existing protocol
entities and context for communication with the wireless device
506.
[0188] Further, the first network node 508 is configured to
transmit a second signal S62 to the wireless device 506. The second
signal S62 comprises information about a change of master node from
the first network node 508 to the third network node 512 and
information to the wireless device 506 to reuse a second set of
existing protocol entities and context for communication with the
third network node 512. Thereby the master node for the wireless
device 506 is changed.
[0189] As mentioned above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
and second sets of existing protocol entities and context may
comprise one or more of the existing protocol entities and context
for communication between the wireless device 506 and the third
network node 512.
[0190] The first network node 508 may be configured to prepare, by
means of a preparing module 1003 configured to prepare, to receive
data from the third network node 512. The preparing module 1003 may
be implemented by or arranged in communication with the processor
1005 of the first network node 508.
[0191] For example and as mentioned above, the first network node
508 may prepare to receive data from the third network node 512 by
setting up a tunnel, e.g. the GTP tunnel, between the first network
node 508 and the third network node 512. A Tunnel Endpoint
IDentifier (TEID) of the GTP tunnel may be the third network node
512.
[0192] The first network node 508 may also comprise means for
storing data. In some embodiments, the first network node 508
comprises a memory 1004 configured to store the data. The data may
be processed or non-processed data and/or information relating
thereto. The memory 1004 may comprise one or more memory units.
Further, the memory 1004 may be a computer data storage or a
semiconductor memory such as a computer memory, a read-only memory,
a volatile memory or a non-volatile memory. The memory is arranged
to be used to store obtained information, data, configurations,
schedulings, and applications etc. to perform the methods herein
when being executed in the first network node 508.
[0193] Embodiments herein for changing master node for the wireless
device 506 may be implemented through one or more processors, such
as the processor 1005 in the arrangement depicted in FIG. 10,
together with computer program code for performing the functions
and/or method actions of embodiments herein. The program code
mentioned above may also be provided as a computer program product,
for instance in the form of a data carrier carrying computer
program code for performing the embodiments herein when being
loaded into the first network node 508. One such carrier may be in
the form of an electronic signal, an optical signal, a radio signal
or a computer readable storage medium. The computer readable
storage medium may be a CD ROM disc or a memory stick.
[0194] The computer program code may furthermore be provided as
program code stored on a server and downloaded to the first network
node 508.
[0195] Those skilled in the art will also appreciate that the
input/output interface 1000, the receiving module 1001, the
transmitting module 1002, and the preparing module 1003 above may
refer to a combination of analog and digital circuits, and/or one
or more processors configured with software and/or firmware, e.g.
stored in the memory 1004, that when executed by the one or more
processors such as the processors in the first network node 508
perform as described above. One or more of these processors, as
well as the other digital hardware, may be included in a single
Application-Specific Integrated Circuitry (ASIC), or several
processors and various digital hardware may be distributed among
several separate components, whether individually packaged or
assembled into a System-on-a-Chip (SoC).
[0196] An example of a method performed by the second network node
510 for changing master node for the wireless device 506 will now
be described with reference to a flowchart illustrated in FIG. 11.
As mentioned above, the wireless device 506, the first network node
508, the second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0197] The method comprises one or more of the following actions.
It should be understood that some actions are optional, that some
actions may be taken in another suitable order and that actions may
be combined.
[0198] Action 1101
[0199] The second network node 510 receives a third signal S63. The
third signal S63 comprises information that the third network node
512 is the master node for the wireless device 506 and information
to the second network node 510 to reuse a third set of existing
protocol entities and context for communication with the wireless
device 506. Thereby the second network node 510 assists in changing
master node for the wireless device 506.
[0200] In some embodiments, the second network node 510 receives
the third signal S63 from the third network node 512.
[0201] As previously above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as a RRC, state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the third
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506.
[0202] This action corresponds to Action 603 described above.
[0203] Action 1102
[0204] The second network node 510 may transmit a third
acknowledgement signal S66 to the third network node 512, which
third acknowledgement signal S66 acknowledges receipt of the third
signal S63.
[0205] This action corresponds to Action 606 described above.
[0206] Action 1103
[0207] In some embodiments, the second network node 510 sets up or
reconfigure a transport network layer entity to the third network
node 512. For example, the transport network layer entity may be a
GPRS Tunneling Protocol (GTP) entity, e.g. a GTP-U entity for
transfer of user data.
[0208] Action 1104
[0209] In some embodiments, the second network node 510 prepares to
receive data from the third network node 512. For example, the
second network node 510 may prepare to receive data from the third
network node 512 by setting up a tunnel using a GPRS Tunneling
Protocol (GTP), e.g. a GTP tunnel, between the second network node
510 and the third network node 512. A Tunnel Endpoint IDentifier
(TEID) of the GTP tunnel may be the third network node 512.
[0210] To perform the method for changing master node for the
wireless device 506, the second network node 510 may be configured
according to an arrangement depicted in FIG. 12. As mentioned
above, the wireless device 506, the first network node 508, the
second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0211] In some embodiments, the second network node 510 comprises
an input and output interface 1200 configured to communicate with
one or more wireless device, e.g. the wireless device 506, or one
or more the network nodes e.g. the first or third network nodes
508,512. The input and output interface 1200 may comprise a
wireless receiver (not shown) and a wireless transmitter (not
shown).
[0212] The second network node 510 is configured to receive, by
means of a receiving module 1201 configured to receive, a signal
from a wireless device, e.g. the wireless device 506 or a network
node, e.g. from the first or third network node 508,512. The
receiving module 1201 may be implemented by or arranged in
communication with a processor 1206 of the second network node 510.
The processor 1206 will be described in more detail below.
[0213] The second network node 510 is configured to receive a third
signal S63, which third signal S63 comprises information that the
third network node 512 is the master node for the wireless device
506 and information to the second network node 510 to reuse a third
set of existing protocol entities and context for communication
with the wireless device 506. Thereby the second network node 510
assists in changing master node for the wireless device 506.
[0214] In some embodiments, the second network node 510 is
configured to receive the third signal S63 from the third network
node 512.
[0215] As previously above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the third
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506.
[0216] The second network node 510 is configured to transmit, by
means of a transmitting module 1202 configured to transmit, a
signal to a wireless device, e.g. the wireless device 506, or to a
network node, e.g. to the first or third network node 508,512. The
transmitting module 1202 may be implemented by or arranged in
communication with the processor 1206 of the second network node
510.
[0217] The second network node 510 is configured to configured to
transmit a third acknowledgement signal S66 to the third network
node 512, which third acknowledgement signal S66 acknowledges
receipt of the third signal S63.
[0218] As mentioned above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
and second sets of existing protocol entities and context may
comprise one or more of the existing protocol entities and context
for communication between the wireless device 506 and the third
network node 512.
[0219] The second network node 510 may be configured to set up, by
means of a setting up module 1203 configured to set up, a transport
network layer entity to the third network node 512. The setting up
module 1203 may be implemented by or arranged in communication with
the processor 1206 of the second network node 510.
[0220] The second network node 510 may be configured to prepare, by
means of a preparing module 1204 configured to prepare, to receive
data from the third network node 512. The preparing module 1204 may
be implemented by or arranged in communication with the processor
1206 of the second network node 510.
[0221] For example, the transport network layer entity may be a GTP
entity, e.g. a GTP-U entity.
[0222] For example and as mentioned above, the second network node
510 may prepare to receive data from the third network node 512 by
setting up a tunnel, e.g. the GTP tunnel, between the first network
node 508 and the third network node 512. A Tunnel Endpoint
IDentifier (TEID) of the GTP tunnel may be the third network node
512.
[0223] The second network node 510 may also comprise means for
storing data. In some embodiments, the second network node 510
comprises a memory 1205 configured to store the data. The data may
be processed or non-processed data and/or information relating
thereto. The memory 1205 may comprise one or more memory units.
Further, the memory 1205 may be a computer data storage or a
semiconductor memory such as a computer memory, a read-only memory,
a volatile memory or a non-volatile memory. The memory is arranged
to be used to store obtained information, data, configurations,
schedulings, and applications etc. to perform the methods herein
when being executed in the second network node 510.
[0224] Embodiments herein for changing master node for the wireless
device 506 may be implemented through one or more processors, such
as the processor 1206 in the arrangement depicted in FIG. 12,
together with computer program code for performing the functions
and/or method actions of embodiments herein. The program code
mentioned above may also be provided as a computer program product,
for instance in the form of a data carrier carrying computer
program code for performing the embodiments herein when being
loaded into the second network node 510. One such carrier may be in
the form of an electronic signal, an optical signal, a radio signal
or a computer readable storage medium. The computer readable
storage medium may be a CD ROM disc or a memory stick.
[0225] The computer program code may furthermore be provided as
program code stored on a server and downloaded to the second
network node 510.
[0226] Those skilled in the art will also appreciate that the
input/output interface 1200, the receiving module 1201, the
transmitting module 1202, the setting up module 1203 and the
preparing module 1204 above may refer to a combination of analog
and digital circuits, and/or one or more processors configured with
software and/or firmware, e.g. stored in the memory 1205, that when
executed by the one or more processors such as the processors in
the second network node 510 perform as described above. One or more
of these processors, as well as the other digital hardware, may be
included in a single Application-Specific Integrated Circuitry
(ASIC), or several processors and various digital hardware may be
distributed among several separate components, whether individually
packaged or assembled into a System-on-a-Chip (SoC).
[0227] An example of a method performed by the third network node
512 for changing master node for the wireless device 506 will now
be described with reference to a flowchart illustrated in FIG. 13.
As mentioned above, the wireless device 506, the first network node
508, the second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0228] The method comprises one or more of the following actions.
It should be understood that some actions are optional, that some
actions may be taken in another suitable order and that actions may
be combined.
[0229] Action 1301
[0230] In order to inform the third network node 512 about a change
of master node, the third network node 512 receives a first signal
S61. The first signal S61 comprises information that the third
network node 512 is to be the master node for the wireless device
506 and information to the third network node 512 to reuse a first
set of existing protocol entities and context for communication
with the wireless device 506.
[0231] As previously above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506. In some embodiments,
the third network node 512 receives the first signal S61 from the
first network node 508 or the wireless device 506.
[0232] This action corresponds to Action 601 described above.
[0233] Action 1302
[0234] In some embodiments, the third network node 512 sets up a
protocol entity. For example, the protocol layer entity may be a
PDCP layer entity for the communication with the wireless device
506.
[0235] Action 1303
[0236] The third network node 512 transmits a second signal S62 to
the wireless device 506, which second signal S62 comprises
information about a change of master node from the first network
node 508 to the third network node 512 and information to the
wireless device 506 to reuse a second set of existing protocol
entities and context for communication with the third network node
512.
[0237] In some embodiments, the third network node 512 transmits
the second signal S62 to the wireless device 506 via the first
network node 508.
[0238] The second set of existing protocol entities and context may
comprise one or more of the existing protocol entities and context
for communication with the third network node 512.
[0239] This action corresponds to Action 602 described above.
[0240] Action 1304
[0241] The third network node 512 transmits a third signal S63 to
the second network node 510, which third signal S63 comprises
information that the third network node 512 is the master node for
the wireless device 506 and information to the second network node
510 to reuse a third set of existing protocol entities and context
for communication with the wireless device 506. After the Actions
1301-1303, the master node for the wireless device 506 is
changed.
[0242] This action corresponds to Action 603 described above.
[0243] Action 1305
[0244] In some embodiments, the third network node 512 transmits a
first acknowledgement signal S64 to the first network node 508 or
the wireless device 506, which first acknowledgement signal S64
acknowledges receipt of the first signal S61.
[0245] This action corresponds to Action 604 described above.
[0246] Action 1306
[0247] In some embodiments, the third network node 512 receives a
second acknowledgement signal S65 from the wireless device 506,
which second acknowledgement signal S65 acknowledges receipt of the
second signal S2.
[0248] This action corresponds to Action 605 described above.
[0249] Action 1307
[0250] In some embodiments, the third network node 512 receives a
third acknowledgement signal S66 from the second network node 510,
which third acknowledgement signal S66 acknowledges receipt of the
third signal S63.
[0251] This action corresponds to Action 606 described above.
[0252] Action 1308
[0253] In some embodiments, the third network node 512 transmits a
fourth signal S67 to a core network node 504, which fourth signal
S67 informs the core network node 504 that the third network node
512 is the master node for the wireless device 506.
[0254] This action corresponds to Action 607 described above.
[0255] To perform the method for changing master node for the
wireless device 506, the third network node 512 may be configured
according to an arrangement depicted in FIG. 14. As mentioned
above, the wireless device 506, the first network node 508, the 30
second network node 510 and the third network node 512 are
operating in the wireless communications system 500. Further, the
first network node 508 is the master node for the wireless device
506, and the second network node 510 and the third network node 512
are secondary nodes for the wireless device 506.
[0256] In some embodiments, the third network node 512 0 comprises
an input and output interface 1400 configured to communicate with
one or more wireless device, e.g. the wireless device 506, or one
or more the network nodes e.g. the first or second network nodes
508,510. The input and output interface 1400 may comprise a
wireless receiver (not shown) and a wireless transmitter (not
shown).
[0257] The third network node 512 is configured to receive, by
means of a receiving module 1401 configured to receive, a signal
from a wireless device, e.g. the wireless device 506 or a network
node, e.g. from the first or second network node 508,510. The
receiving module 1401 may be implemented by or arranged in
communication with a processor 1404 of the third network node 512.
The processor 1404 will be described in more detail below.
[0258] The third network node 512 is configured to receive a first
signal S61, which first signal S61 comprises information that the
third network node 512 is to be the master node for the wireless
device 506 and information to the third network node 512 to reuse a
first set of existing protocol entities and context for
communication with the wireless device 506.
[0259] As previously above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as a RRC, state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the first
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication with the wireless device 506.
[0260] The third network node 512 may be configured to receive the
first signal S61 from the first network node 508 or the wireless
device 506.
[0261] In some embodiments, the third network node 512 is
configured to receive a second acknowledgement signal S65 from the
wireless device 506, which second acknowledgement signal S65
acknowledges receipt of a second signal S62 transmitted from the
third network node 512 to the wireless device 506.
[0262] The third network node 512 may further be configured to
receive a third acknowledgement signal S66 from the second network
node 510, which third acknowledgement signal S66 acknowledges
receipt of the third signal S63.
[0263] The third network node 512 is configured to transmit, by
means of a transmitting module 1402 configured to transmit, a
signal to a wireless device, e.g. the wireless device 506, or to a
network node, e.g. to the first or second network node 508,510. The
transmitting module 1402 may be implemented by or arranged in
communication with the processor 1404 of the third network node
512.
[0264] The third network node 512 is configured to transmit the
second signal S62 to the wireless device 506, which second signal
S62 comprises information about a change of master node from the
first network node 508 to the third network node 512 and
information to the wireless device 506 to reuse a second set of
existing protocol entities and context for communication with the
third network node 512.
[0265] Further, the third network node 512 is configured to
transmit a third signal S63 to the second network node 510, which
third signal S63 comprises information that the third network node
512 is the master node for the wireless device 506 and information
to the second network node 510 to reuse a third set of existing
protocol entities and context for communication with the wireless
device 506. Thereby the master node for the wireless device 506 is
changed.
[0266] As mentioned above, the existing protocol entities and
context may comprise one or more RLC entities and/or one or more
MAC entities, and wherein the context comprises one or more of:
state information such as an RRC state; security-related
information such as a security capability or a key material; a UE
identity such as an identity of a UE-associated logical
S1-connection; and a UE radio access capability. Thus, the second
set of existing protocol entities and context may comprise one or
more of the existing protocol entities and context for
communication between the wireless device 506 and the third network
node 512. Further, the third set of existing protocol entities and
context may comprise one or more of the existing protocol entities
and context for communication between the second network node 510
and the wireless device 506.
[0267] In some embodiments, the third network node 512 transmit a
first acknowledgement signal S64 to the first network node 508 or
the wireless device 506, which first acknowledgement signal S64
acknowledges receipt of the first signal S61.
[0268] The third network node 512 may transmit a fourth signal S67
to a core network node 504, which fourth signal S67 informs the
core network node 504 that the third network node 512 is the master
node for the wireless device 506.
[0269] The third network node 512 may be configured to set up, by
means of a setting up module 1403 configured to set up, a protocol
layer entity. The setting module 1403 may be implemented by or
arranged in communication with the processor 1405 of the third
network node 512.
[0270] The third network node 512 may also comprise means for
storing data. In some embodiments, the second network node 510
comprises a memory 1404 configured to store the data. The data may
be processed or non-processed data and/or information relating
thereto. The memory 1404 may comprise one or more memory units.
Further, the memory 1404 may be a computer data storage or a
semiconductor memory such as a computer memory, a read-only memory,
a volatile memory or a non-volatile memory. The memory is arranged
to be used to store obtained information, data, configurations,
schedulings, and applications etc. to perform the methods herein
when being executed in the third network node 512.
[0271] Embodiments herein for changing master node for the wireless
device 506 may be implemented through one or more processors, such
as the processor 1405 in the arrangement depicted in FIG. 14,
together with computer program code for performing the functions
and/or method actions of embodiments herein. The program code
mentioned above may also be provided as a computer program product,
for instance in the form of a data carrier carrying computer
program code for performing the embodiments herein when being
loaded into the third network node 512. One such carrier may be in
the form of an electronic signal, an optical signal, a radio signal
or a computer readable storage medium. The computer readable
storage medium may be a CD ROM disc or a memory stick.
[0272] The computer program code may furthermore be provided as
program code stored on a server and downloaded to the third network
node 512.
[0273] Those skilled in the art will also appreciate that the
input/output interface 1400, the receiving module 1401, the
transmitting module 1402, and the setting up module 1403 above may
refer to a combination of analog and digital circuits, and/or one
or more processors configured with software and/or firmware, e.g.
stored in the memory 1404, that when executed by the one or more
processors such as the processors in the third network node 512
perform as described above. One or more of these processors, as
well as the other digital hardware, may be included in a single
Application-Specific Integrated Circuitry (ASIC), or several
processors and various digital hardware may be distributed among
several separate components, whether individually packaged or
assembled into a System-on-a-Chip (SoC).
Exemplifying Embodiments
[0274] As schematically illustrated in FIGS. 15 and 16 two protocol
architectures may be provided for a cluster, e.g.
multi-connectivity, in an NX communications network.
[0275] FIG. 15 schematically illustrates a first protocol
architecture comprising one RRC connection between the UE, e.g. the
wireless device 506, and the MeNB, e.g. the first network node 512,
in the cluster, e.g. the communications network 500. In FIG. 15,
the MeNB is also referred to as a Cluster Head (CH), and each of
the SeNBs is also referred to as a Serving Access Node (SAN).
[0276] FIG. 16 schematically illustrates a second protocol
architecture wherein each eNB, e.g. the first, second, and third
network nodes 508,510,512, in the cluster, e.g. the communications
network 500, has one RRC connection with the UE, e.g. the wireless
device. The RRC of the MeNB is referred to as an Anchor RRC and the
RRC of the SeNB is referred to as an Assisting RRC.
[0277] In the first protocol architecture, the RRC handling is an
extension of LTE DC, and in the second protocol architecture, the
assisting RRC at each SeNB, e.g. at the second and third network
nodes 510,512, also set ups a UE context according to the
information from the anchor RRC in the MeNB, e.g. the first network
node 508. Assisting RRC may communicate with the UE directly using
its own security key, e.g. its own S-KeNB. Since the UE maintains
multiple Signal Radio Bearer (SRB) connections within the cluster,
the UE needs to know how to send a signal, e.g. a packet, in the
uplink to the right network node. In order to solve this issue, the
logical channel ID assigned to the SRB between each network node
and the UE must be unique among the nodes comprised in the cluster.
The value of logical channel ID for SRB needs to use more values
than those defined in LTE, i.e., 0, 1, 2.
Signaling Procedure for Enabling Fast Role-Switch
[0278] A signaling procedure for enabling fast role-switch will now
be described with reference to FIG. 17. Consider the case when the
MeNB, e.g. the first network node 508, actively requires one SeNB,
e.g. the third network node 512, to switch roles in the cluster.
For example, this may be due to that the average radio link quality
between the UE, e.g. the wireless device 506, and the respective
SeNB, e.g. the second and/or third network node 510,512, is better
than the serving MeNB, e.g. the first network node 508.
[0279] Exemplifying signaling procedures for both the first and
second protocol architectures are given below in FIG. 17.
[0280] As is illustrated in FIG. 17, the signaling either between
different eNBs within the cluster or the signaling between the UE
and the cluster are all simplified. Yet, there are some differences
between the first protocol architecture and the second protocol
architecture, which is mainly about what needs to be done.
[0281] For the first protocol architecture, firstly, the old MeNB,
e.g. the first network node 508, asks the SeNB, e.g. the third
network node 512, to get prepared to be the new MeNB. This may be
done by the first network node 508 transmitting the first signal
S61 to the third network node 512.
[0282] Secondly, if there is not a secondary cell group (SCG)
bearer at the SeNB, e.g. at the third network node 512, the old
MeNB, e.g. the first network node 508, needs to deliver a key
S-KeNB to SeNB so that the SeNB is able to derive the key used for
RRC and user plane. If there is already SCG bearer at the SeNB, the
SeNB just needs to derive the key for RRC.
[0283] Thirdly, the SeNB, e.g. the third network node 512 (new
MeNB), then prepares a Signaling Radio Bearer (SRB) between itself
and the UE, e.g. the wireless device 506. That is, the third
network node 512 sets up PDCP entity for RRC message. By means of
SRB diversity, an RLC entity is already there in the SeNB, so it is
not necessary to remove and set up a new RLC entity, the existing
RLC entity is to be reused.
[0284] Fourthly, the SeNB (new MeNB) then set ups the PDCP entity
for the split data bearer. Its existing RLC entity for split bearer
is to be reused.
[0285] Fifthly, the Old MeNB informs the UE that there is a role
switch in the cluster. This may be done by transmitting the second
signal S62 to the wireless device 506. Then the UE set ups the SRB
with the new MeNB, e.g. the third network node 512. If there is no
SCG bearer at the SeNB (new MeNB), the UE derives the S-KeNB from
the message received by the old MeNB, e.g. the first network node
508, and then the key for RRC and user plane. If there is already a
SCG bearer at the SeNB, the UE already knows the security key, e.g.
the S-KeNB, and therefore it is able to derive the key for RRC of
the new MeNB directly. The UE reconfigures its PDCP entity for
SRB/DRB, and all the RLC entity is to be remained.
[0286] Sixthly, the new MeNB, e.g. the third network node 512,
informs the other SeNB, e.g. the second network node 510, in the
cluster that it is MeNB now. This may be done by transmitting the
third signal S63 to the second network node 510. TheoOther SeNB
does not need to do anything except for configuring its transport
protocol to prepare to receive signaling/data from the new
MeNB.
[0287] Seventhly, the new MeNB informs the Core Network (CN), e.g.
a Gateway (GW) or an Mobility Management Entity (MME), that it is
MeNB now. This may be done by transmitting the fourth signal S67 to
the CN node. The CN then delivers packets to new MeNB.
[0288] For the second protocol architecture, firstly, the old MeNB,
e.g. the first network node 508, asks the SeNB, e.g. the third
network node 512, to get prepared to be the new MeNB. This may be
done by transmitting the first signal S61. The SRB at SeNB (new
MeNB) is to be reused; nothing needs to be changed/updated in this
case.
[0289] For a split data bearer, the SeNB (new MeNB) set ups the
PDCP entity for split data bearer. Its existing RLC entity for the
split bearer is to be reused.
[0290] For a SCG data bearer, nothing needs to be updated at the
SeNB (new MeNB). The SCG data bearer will be the MCG data
bearer.
[0291] Secondly, the old MeNB informs the UE that there is a role
switch in the cluster. This may be done by transmitting the second
signal S62. The SRB at the UE does not need to be updated. The UE
reconfigures its PDCP entity for split data radio bearer (DRB), all
the RLC entity is to be remained.
[0292] Thirdly, the new MeNB, e.g. the third network node 512,
informs the other SeNB, e.g. the second network node 510, in the
cluster that it is MeNB now. This may be done by transmitting the
third signal S63 to the other SeNB. The other SeNB does not need to
do anything except to configure its transport protocol to prepare
to receive signaling/data from the new MeNB.
[0293] Fourthly, the new MeNB informs the CN that it is the MeNB
now. This may be done by transmitting the fourth signal S64 to the
CN. The CN then deliver packets to the new MeNB, e.g. the third
network node 512.
Signaling Procedure for Guaranteeing System Availability
[0294] An exemplifying signaling procedure for guaranteeing system
availability will now be described with reference to FIG. 18.
[0295] Consider the case that the current MeNB suddenly becomes
unavailable i.e., out of service, and one of the SeNB needs to be
upgraded to the MeNB role so as to guarantee the system
availability target e.g., which is set by the mission-critical MTC
services.
[0296] In order to have a fast SeNB role upgrade to MeNB, the
second protocol architecture described above may be preferred. This
is because that the SRB is already set up between the UE and each
SeNB, the S-KeNB is known by both the UE and the SeNB, i.e., UE
context including security is already there in the SeNB, and the UE
and the SeNB is able communicate with each other directly without
first going into the idle mode and then setting up the connection.
An exemplifying signaling procedure is shown in FIG. 18. Since
either the network or the UE can detect failure of the old MeNB,
the first message to recover the cluster may be either initiated by
the UE or by the network via new MeNB.
[0297] An exemplifying procedure will now be described.
[0298] Firstly, a master failure, e.g. a MeNB connection failure or
a MeNB node failure, is detected by means of a missing alive
signaling between the MeNB, e.g. the first network node 508, and
the SeNB, e.g. the third network node 512, or by the UE reporting
failure of MCG to the SeNB. After detecting failure of MCG, the UE
sends RRC re-establishment request to the SeNB using the security
key, e.g. the S-KeNB, via the SRB between itself and one of the
SeNB with the cause value set to `MeNB failure`. This may be done
by transmitting the first signal S61 to the SeNB, e.g. the third
network node 512. The SeNB can decode the RRC message using its
S-KeNB. When notice that the cause value is `MeNB failure`, SeNB
can perform step 2. This is different from normal RRC
re-establishment which is preceded by RLF and random access,
causing UE connection interruption. A signal may be transmitted
from the MeNB, e.g. the first network node 508, to the SeNB, e.g.
the third network node 512, in case it notices loss of connectivity
with the UE, e.g. the wireless device 506.
[0299] Secondly, the SeNB, e.g. the third network node 512,
performs necessary steps to acquire the MeNB role or the eNB role
in case there is no other SeNB in the cluster. This may be done by
the SeNB informing the UE, e.g. the wireless device 506, that it
accepts the MeNB role, bu for example transmitting the second
signal S62 to the wireless device 506. Further, since the SeNB,
e.g. the third network node 512, has the SRB connection with the
UE, the SeNB is able to send an RRC message to the UE directly
using the security key, e.g. the S-KeNB. When the UE receives and
deciphers this message, what UE needs to do is just to reconfigure
its PDCP entity for split data bearer, and release resource
corresponding to the old MeNB, e.g. the first network node 508.
Other things is to be remained.
[0300] Secondly, the SeNB, e.g. the third network node 512, informs
the other SeNB(s), e.g. the second network node 510, in the cluster
that it is the new MeNB. This may be done by transmitting the third
signal S63 to the second network node 510. The other SeNB does not
need to do anything except for updating its transport layer to be
prepared to receive from the new MeNB.
[0301] Thirdly, the SeNB, e.g. the third network node 512, informs
the CN that it is the new MeNB. This may be done by transmitting
the fourth signal S64 to the CN. The CN relocates the S1 connection
from the old MeNB, e.g. the first network node 508, to the SeNB,
e.g. the third network node 512. The CN then starts to deliver data
to the new MeNB, e.g. the third network node 512. Further, the
SeNB, e.g. the second network node 510, releases X2 connection with
the old MeNB, e.g. the first network node 508. By means of this
procedure, the SeNB, e.g., the third network node 512, is able be
upgraded into a master node very quickly and enables
mission-critical MTC use cases that require extreme latency,
reliability and availability requirements.
[0302] It should be understood that, even more embodiments may be
obtained by minor modifications of the embodiments disclosed
herein.
[0303] When the word "comprise" or "comprising" is used in this
disclosure it shall be interpreted as non-limiting, i.e. meaning
"consist at least of".
[0304] The embodiments herein are not limited to the above
described preferred embodiments. Various alternatives,
modifications and equivalents may be used. Therefore, the above
embodiments should not be taken as limiting the scope of the
invention, which is defined by the appending claims.
* * * * *